There are several ways to find out the present working mode, for example from an Online Mode menu or its display in a Toolbar. This option is accessible if communication was successfully established with a PLC controller. If we choose a mode that differs from a present one, change of mode will be momentary.
In order to avoid an accidental change of PLC controller mode, there is an option that obliges a computer to ask a question before each mode change, whether that is the option a user really wants (this option is included as default). PLC controller has three modes in class C, MONITOR, RUN and PROGRAM/STOP mode.